METHOD OF DETERMINING MINIMAL INHIBITORY CONCENTRATION OF ANTIMICROBIAL PREPARATION

摘要

FIELD: biotechnology.SUBSTANCE: microorganism-causative agent is isolated from the biological material of the patient. The standard suspension of the isolated microorganism-causative and two-fold dilutions of antibacterial preparations with known activity is prepared. Inoculation is carried out. The standard suspension of the isolated causative agent with the volume of 0.1 ml is mixed with 5.0 ml of liquid nutrient medium specific for this pathogen. It is incubated for 24 hours at +37°C. The test 1:100 and control 1:200 dilutions are prepared in the same nutrient medium. Each of the two-fold dilutions of antibacterial preparations in amount of 0.075 ml with an equal amount of the test dilutions is applied in the test cavities of the plate. In the control cavity 0.150 ml of control dilution is applied and incubated for 48 hours at + 37°C. The liquid fraction of the suspension is removed from the cavities. For staining 0.2 ml of 1% solution of crystal violet is added to each cavity. It is exposed at room temperature for 30 min. The contents of the cavities are washed three times with distilled water and 0.2 ml of 99% solution of dimexidum is added to each cavity. It is exposed at room temperature for 15 minutes. The optical density of the medium in the control (OD) and the test cavities is measured in the optical units (pu) in a microplate reader at the wave-length of 540 nm. When fulfilment of the condition OD> 0.2pu, the greatest two-fold dilution of antibacterial preparation in the test cavity with an optical density less than 0.2 pu is defined as the minimum inhibitory concentration (MIC).EFFECT: invention enables to improve the accuracy of determination of IPC.2 ex